As well as overseeing the authorisation of medicines in the European Union, the European Medicines Agency – soon to be moved out of the UK – is at the centre of a European web of pharmacovigilance, or the monitoring of drugs to prevent any nasty surprises.

EU law requires companies that sell medicines in the EU to designate a so-called QPPV – a qualified person for pharmacovigilance. That person must be based in the European single market, which the UK is on track to leave. There are about 150 QPPVs in the UK, who now face the relocation of their functions to other EU countries.

Behind every QPPV, there are often very large teams, meaning the impact of Brexit will be multiplied far beyond the 150 contact people. In preparation for the post-Brexit world, companies must decide to what extent they should move their EU-related pharmacovigilance activities out of the UK. Such decisions could be tough on British specialists in the field – the way things are going, they will no longer have the right to work in another EU country after 2019.

Beyond the potential human disruption, however, pharma companies worry the UK will be cut off from the medicines agency's databases and networks, in particular its Pharmacovigilance Risk Assessment Committee, which the UK currently chairs. The big fear is patient safety will be put at risk because barriers to information sharing will go up. If concerns are raised in, say, Spain about adverse reactions to a medicine, which in the current system would be notified to all other EU countries, the UK might be late in hearing about it, and would be outside the discussions of what to do about it.

Meanwhile, under the EU's Brexit “negotiating directives” the UK must pay the costs of the relocation of the medicines agency, on the basis it's the UK's fault the agency is relocating. The UK taxpayer would therefore have to buy the agency out of its lease with Canary Wharf Group, which is owned by Qatari and Bermuda-based investors. Unfortunately, under a deal signed in 2011, when Brexit was merely a twinkle in Nigel Farage's eye, that lease runs to 2039. No termination clause was included and the expected cost is about £300 million. Oops!